This site mainly focuses on the design aspects of a portfolio but here’s one where the technology behind it is unique (the design work is good too). Andrew Sliwinski, a graphic and user experience designer living near Detroit, has developed a framework using Yahoo! Pipes that aggregates and consumes data from a network of nodes (Flickr, Blogspot, Twitter, Del.icio.us) and displays it on his site. So when the network is updated, the content or data gets added to the portfolio. Andrew is basically using these sites as a back-end CMS tool to edit and manage his portfolio. Brilliant.
You can read a detailed explanation of the technology here.